A Power-Frequency Controller With Resonance Frequency Tracking Capability for Inductive Power Transfer Systems

A self-tuning controller for power transfer regulation in inductive power transfer (IPT) systems is proposed in this paper. The controller enables power transfer regulation around a user-defined reference power level. The converter's efficiency is improved by constantly tuning the switching operations to the resonant current, thereby achieving the soft-switching operations reducing electromagnetic interference in the power converters. The self-tuning capability makes it ideal for dynamic IPT systems with uncertain loads and fluctuating resonance frequency. High operating frequencies can be achieved using the simplified digital circuit design for the controller, proposed in this paper, which delivers a low total propagation delay. Bidirectional power transfer can be enabled by using the proposed controller on both transmitter and receiver sides. In the reverse power flow mode, the primary converter operates as a rectifier and the power transfer is controlled through the secondary converter using the proposed controller. The performance of the proposed controller is analyzed using MATLAB/Simulink and the results are presented. Finally, the proposed controller is implemented experimentally and its performance is evaluated as a case study on an IPT system. The experimental and simulation results conform to each other, and show that the proposed converter can effectively regulate the power transfer with an improved efficiency.